1. Field of the Invention
The invention relates to a method and devices for treatment of living cells with a cold atmospheric pressure plasma with simultaneous selective electroporation of the cells being treated. The invention provides for local, selective killing of cancer cells, for improvement of the treatment of wounds and for an improved antimicrobial plasma effect.
2. Description of the Related Art
1. Cancer Therapy:
The standard methods of cancer therapy used individually or in combination are currently surgery, chemotherapy and radiation therapy. A method known as “electroporation therapy” (EPT), “electrochemotherapy” (ECT) or “high-voltage impulse therapy” (HVIT) is now undergoing clinical trials. This method is based on the fact that the membrane pores of cancer cells can be selectively and reversibly opened for a short time by selective application of pulsed electric fields (electroporation), thus achieving significantly increased cell absorption of the active ingredients used for chemotherapy, such as bleomycin or cisplatin. The advantages compared with conventional chemotherapy include 1) the necessary dose of active ingredient can be reduced by a factor of approximately twenty with electrochemotherapy, and that, by virtue of the selective killing, a tissue-preserving effect with minimal scarring can be achieved, as can a large reduction of the side effects caused by the chemotherapeutic agent. Since the cancer cells differ from the healthy cells in terms of size, cell-membrane structure and electrical properties, selectivity of electroporation can be achieved by suitable choice of amplitude, number, duration and frequency of the high-voltage impulses. German patent documents DE 69604509, DE 69928383 and DE 60106901 describe various devices for achieving such controlled, selective electroporation of cells.
Even though the dose of active ingredient may be considerably reduced in electrochemotherapy, it is not possible to dispense completely with the use of expensive chemotherapeutic agents, which still have side effects for healthy body tissue, albeit to a lesser extent than in conventional chemotherapy.
2. Healing of Chronic Wounds:
Since chronic wounds are usually the consequence of basic diseases, the primary approach to curing them lies in diagnosis and causal therapy of the basic ailment. In many cases, however, curing of the basic disease is not possible, and so it is endeavored by diverse local therapeutic measures, such as surgical interventions, wound cleaning and disinfection, the use of antibiotics and of special wound dressings and bandages, to achieve healing of the wound despite persistence of the basic disease.
The constantly growing range of available therapeutic agents (salves, tinctures, powders, antiseptics, antibiotics) as well as bandage materials and systems of bandaging substances for treatment of chronic wounds, and the associated problem of the correct choice and application, may lead to a therapeutic procedure that is characterized by a large number of diverse, uncoordinated and often ineffective medical measures (poly-pragmatism) and may be the cause of healing delays and cost increases.
3. Sterilization, Decontamination and Processing of Medical Technical Products:
The use of the known standard methods for thermal, chemical, UV and gamma-ray sterilization may be no longer possible for a growing number of medical technical products, because of material-related, construction-specific as well as environmental and health concerns. Therefore, the development of methods for material-preserving and effective antimicrobial treatment is becoming increasingly important. Plasma-related methods may offer interesting possibilities for addressing this problem and intensive effort to the development of this technology is in progress throughout the world.
Pathogen kill rates on the order of the 6-log reduction necessary for sterilization and material-preserving decontamination of medical technical products of sensitive, thermally labile materials have been achieved employing plasma technology, although only for some relevant microorganisms. However, the potential utility of this technique has not been fully exhausted.